## Physics MCQs Topic Optics

1.light of wavelength lambda is incident normally on a diffraction grating for which the slit spacing is equal to 3 lambda.what is the sine of angle between the second order maximum and the normal?
a.1 / 6
b.1 / 3
c.2 / 3
d.3 / 2

2. Light of wavelength lambda is incident normally on a diffraction grating for which the slit spacing is equal to         3 lambda.what is the sine of angle between the second order maximum and the normal?
a.1 / 6
b.1 / 3

c.2 / 3
d.3 / 2

3.a diffraction grating has 500 lines per mm its slit spacing will be
a.5*103  mm
b.5*10-3 mm
c.2*103 mm

d.2*10-3 mm

4.for which of the following colors will the fring width be minimum in the double slit experiment?
a.violet
b.red
c.green
d.yellow

5. in single slit experiment, increasing the width of slit results in
a. widening the diffraction pattern
b. narrowing the diffraction pattern
c. no change in the diffraction pattern
d. reversing the diffraction pattern

6.increasing the number of lines per centimeter (the ruling) on diffraction grating
a.allows one to use longer wavelengths of light
b.allows one to use shorter wavelengths of light
c.increases the spread of the spacing between principal maxima
d.decreases the spread of the spacing between principal maxima

7. the spreading of light from its original line of travel is called
a. reflaction
b. refraction
c. diffraction
d. dispersion

8. in double slit interference pattern , using different wavelength of light to produce the fringes , the fringes are closer together when the slit is illuminated with
a. blue light
b.green light
c. yellow light
d. orange light
e. 677nm

9.in double-slit interference pattern, destructive interfernce occurs when the path difference between two waves is
a.even multiples of lambda by 2
b.odd multiples of lambda by 2
c.the same
d.even multiples of lambda
e.odd multples of lambda

10.in double-slit interference pattern, decreasing the distance, d, between the slits causes  the width of the fringes to
a.increase
b.decrease
c.remain the same
d.increase then decrease
e.decrease then increase

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